The Data-Over-Cable Service Interface Specification (DOCSIS) has been established by cable television network operators to facilitate transporting data traffic, primarily Internet traffic, over existing community antenna television (CATV) networks. In addition to transporting data traffic, as well as television content signals over a CATV network, multiple services operators (MSO) also use their CATV network infrastructure for carrying voice, video on demand (VoD) and video conferencing traffic signals, among other types.
In transporting downstream multimedia content, as well as data, upstream messages are typically sent to request the content and to set up a service flow to deliver the content. In addition to downstream multimedia content, such as video, voice traffic also uses message signaling to set up service flows for the upstream and downstream directions.
These signals are typically sent over a fiber network to a location, sometimes referred to as a node, near an end user, and from the node to a broadband user's device via a coaxial cable. Such an arrangement is known in the art as a hybrid fiber coax network (HFC).
Network interface devices, such as cable modems, are one manner in which the MSOs meet the demand for increased bandwidth capabilities in delivering information from a central location, such as a headend, over the HFC networks to users, such as residential and commercial end users.
Dual mode cable modems, for example, are designed to be used in either DOCSIS or EuroDOCSIS environments. These dual mode cable modems can be used to reduce inventory demands for two separate types of modems, and the associated costs of maintaining and deploying separate sets of inventory. Dual mode cable modems can operate using either the 6 MHz North American DOCSIS frequency allocation plan or an 8 MHz EuroDOCSIS frequency allocation plan. When placing a dual mode cable modem in service, the cable modem initially has no way of identifying whether it is deployed in a North American DOCSIS system or a EuroDOCSIS system, or even whether it has been re-deployed from one to the other.
Additionally, dual mode cable modems include both North American DOCSIS and EuroDOCSIS baseline privacy interface (BPI) certificates. BPI certificates provide a data encryption scheme to protect data sent to and from cable modems in a DOCSIS or EuroDOCSIS system. This data encryption gives cable subscribers data privacy across the RF network between cable modem termination systems (CMTS) at the headend and the cable modem at the customer site. BPI certificates are chained to a different type authority depending on whether they are used in a North American DOCSIS system or a EuroDOCSIS system. The dual mode cable modem must determine which standard is in use so as to use the correct certificates.
Accordingly, there is a need for initialization of a dual mode cable modem that can recognize which type system it is deployed in, whether DOCSIS or EuroDOCSIS, and for quickly re-initializing itself upon determination that it is set up for BPI certificates that do not match the system in use by the headend cable plant.